Preliminary Study On The Cable Force Optimization Of Cantilever Construction Of Reinforced Concrete Arch Bridge With Part Of Stiff Skeleton

The reinforced concrete arch bridge has the advantages of large bearing capacity,clear stress state,reasonable economy and so on,which is one of the ideal bridge types in good geological conditions.With the development of economy and technology,more and more large span concrete arch bridge appeared,and the bridge construction method has been developing in the direction of adapting to the construction of large span arch bridge.In recent years,large span concrete arch bridges are mostly constructed by cantilever construction and dynamic skeleton construction.The construction methods of large span arch bridges are mainly used in the cantilever construction and stiffening skeleton construction.Arch bridge cantilever pouring construction rely on hanging basket site pouring arch section.And the cable buckle hanging arch section and tension,until the concrete strength meet the requirements.The other end of the cable anchorage in the temporary tower.The other side of the temporary tower is anchored to the rear anchor block with steel strand.The cable-stayed system can reduce the negative bending moment of the arch ring and ensure the safety of the arch ring during the construction.After the arch close,the temporary cables will be removed.It is very important to determine the cable tension force of the temporary cable for the safety of the cantilever construction of the arch bridge and to achieve a reasonable bridge state The main contents of this paper are as follows:(1)First of all,the development status quo of cantilever construction of concrete arch bridge,the research status of cable force optimization and the construction technology of concrete arch bridge are investigated In this paper,the common construction methods of concrete arch bridge and the calculation method of cable force optimization are described in detail.(2)The stress state of the arch ring with the cantilever construction of reinforced concrete arch bridge determine that the cable force is mainly controlled by the stress of arch ring,and the control line is supplemented.The traditional optimization method can not optimize the stress level directly,and can not make the whole process of the arch ring structure optimum.Therefore,this paper puts forward an optimal theory of cable force in the whole construction process,the core is to find the balance point between the maximum bending moment in the construction stage.The mechanical basis is introduced,the influence of the angle of the cable and the position of the lifting point is analyzed.(3)Since the main arch of reinforced concrete arch bridge does not need to be provided with prestressed reinforcement,the casting process is the most unfavorable state of the arch.Therefore,it is not necessary to consider whether the force of the arch ring is the same as the internal force after the bridge is completed.Only need to meet the internal force optimization in the construction stage to ensure the safety of arch ring during construction.The initial cable force is calculated by using the Midas cable force optimization function to meet the maximum internal force and alignment requirements,then the initial cable force is optimized by the improved stress balance method to ensure the stress in the whole process of arch construction.(4)Using space beam element simulate the rigid frame,and plate element simulate the concrete wrapped outside to make calculation and analysis in the construction process of the right framework.(5)The construction control scheme of Wujiang bridge double track bridge is determined,and the stress and alignment of the arch ring in the construction stage are mainly monitored.The monitoring data of construction site should be calculated and analyzed in time,compared with the theoretical values extracted from the computational model.The comparison results are helpful to the next modification of the control parameters.